<html>
<body>

<script>
addEventListener('load', function() {
  setTimeout(function() {
    var a = document.getElementById('audio');
    a.onplay = function() {
      alert('onplay');
    };
    a.play();
  }, 0);
});
</script>

<audio id='audio' loop src='silence.ogg'>

</body>
</html>
